Rotary brushing tool



Feb. 27, 1968 B. E. NELSON ROTARY BRUSHING TOOL Filed Feb. 27, 1967 INVENTOR BROOKS E. NELSON a 99 g ZFTTORNEYS United States Patent 3,370,313 ROTARY BRUSHING TOOL Brooks E. Nelson, Chagrin Falls, Ohio, assignor to The Gsborn Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Filed Feb. 27, 1967, Ser. No. 618,912 9 Claims. (Cl. 15-198) ABSTRACT OF THE DISCLOSURE A power driven rotary end brush having a cup-shaped holder with a constricted but outwardly flared lip to facilitate radially outward flexing of the brush material under the influence of centrifugal force, with the central portion of the tool within the cup being unobstructed to permit inward bulging and arcuate flexing of the brush material in the region of attachment of the same.

The present invention relates as indicated to a novel rotary brushing tool and more particularly to a power driven rotary end brush having a generally cup-shaped holder with provision for rotating the same about its central axis, such tool falling in the same general class as that exemplified by the end brushes disclosed in Charvat Patent 2,989,767, Charvat Patent 3,147,503, and Less Patent 3,106,739.

The power driven rotary end brushes have been utilized for a great many years for a variety of purposes including the brushing of the bottom surfaces of holes or recesses in metal workpieces and the like. They are frequently subjected to severe working stresses in use and a principal problem has been their relatively short working life due to long fracture of the bristles; indeed,

end brushes having twisted wire tufts of brush bristle material may sometimes have a useful life of as little as two or three minutes under severe working conditions. Not only'does the cost of such brushes become quite high as a result of such short useful life, but the necessary frequent replacement of the same in the chucks of the power driven tools seriously interrupts the continued operation of the latter. This problem is especially serious when utilizing relatively fine gauge bristle wire in the brush. 7

It is accordingly an important object of the present invention to provide a power driven rotary end brush of generally conventional type which will nevertheless have a very much enhanced useful life with a consequent saving in brush cost to the operator as well as very greatly reducing the down time of the equipment mounting the same. Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a side view of the new end brush of this invention;

FIG. 2 is a bristle end view of the brush of FIG. 1;

FIG. 3 shows a longitudinal section taken on the line 33 of FIG. 1;

FIG. 4 shows a somewhat modified embodiment of the invention in longitudinal section corresponding to FIG. 3; and

FIG. 5 is an isometric view of the inner brush element to which the brush bristle material is directly secured.

3,373,313 Patented Feb. 27, 1968 Now referring more particularly to said drawing and especially to FIGS. 1, 2 and 3 thereof, the embodiment of the invention there illustrated comprises a metal (ordinarily steel) cup-shaped body or holder 1 having a stern portion 2 extending axially therefrom for the purpose of securing the same in the usual chuck or gripping device of an appropriate rotary tool. The brush bristle material will normally preferably be formed of a plurality of twisted tufts or knots 3 of relatively fine gauge wire which are directly secured to a deformed sheet metal disc 4. Such disc is provided with a plurality of apertures 5 adjacent the outer periphery thereof through which individual tufts of wire bristle material are passed and then twisted upon themselves as shown in FIG. 5 of the drawing. The outer perihperal portion of the sheet metal disc 4 which is thus apertured to receive the bight portions of such tufts is dished as best shown in FIGS. 3 and 4 so as to form a peripheral flange extending generally parallel to the axis of rotation of cup 1 and its central stem 2. Additionally, a number of smaller apertures such as 6 (FIG. 5) may be punched in member 4 radially inwardly of the circle of apertures 5 to facilitate the cupping or dishing of disc 4 referred to above.

The assembly of the dished brush bristle holding disc 4 and the tufts 3 is then tightly fitted within cup 1 and the outer portion of the latter is necked in at 7 immediately beyond the folded bight portions of the bristle tufts, as shown, to secure such assembly within the cup. The lip 3 of such cup immediately adjacent such necked portion is recurved or flared outwardly to support the tufts less tightly and to facilitate radial outward flexing of the tufts under the influence of centrifugal force in use. It will thus be seen that cup 1 is relatively shallow, being only of the depth required to receive dished disc 4 and the bight portions of the tufts secured thereto, by far the larger longitudinal extent of the tufts protruding from the cup and being thereby enabled to perform the desired brushing action on the work.

While the brush tuft assembly may thus be adequately secured within cup 1- as described, it is frequently desirable further to secure the same in place as well as to resist any tendency of relative rotation of disc 4 and cup 1 in use by providing a central opening 9 in disc 4 through which an axial stud portion 10 may protrude from the bottom of cup 1 as shown in FIG. 4, the end of such stud bei g upset firmly to rivet disc 4 in place.

The resultant power driven rotary end brush affords a brushing face which is hollow in its center (FIG. 2) and does not clamp or restrict the radially inner sides of the bight portions of the bristle tufts 3. In consequence, when the brush is rotated about its axis at high speed in use, the brush bristle tufts are enabled to flex outwardly around curved lip 8 into generally radially disposed positions without incurring undue localized concentration of stress at either the outer sides or inner sides of such tufts. Indeed, the radially inner sides of the tufts are enabled to arc or bulge somewhat in directions radially inwardly of the tool in view of the completely open center of the latter. While the end brushes illustrated in the drawing show relatively small circles of brush tufts 3 it will be understood that cup 1 may be of any desired diameter with a corresponding larger circle of tufts. As indicated above, the present invention is particularly advantageous in the case of brushes utilizing relatively fine gauge brush bristle wire on the order of .006" or .008" in diameter. Twisted tufts or knots of such fine gauge wire tend to untwist to a considerable extent in use, but they are nevertheless well retained by the construction illustrated and described above. It is even possible thus to utilize brush material inserted through apertures 5 and bent into general hairpin configuration without necessarily twisting the same. If twisted tufts of 3 brush bristle wire of a diameter of .020, for example, are employed such tufts will not normally untwist to any consequential extent under conditions of normal use.

As a result of the novel construction of the present invention an extraordinary increase in normal brush life has been achieved, it being found that the useful life of a brush in accordance with the invention may, for example, be on the order of 1 to 1 /2 hours, Whereas the most nearly comparable prior art brush of which applicant is aware has a useful life of only several minutes under the same working conditions. Such benefits are especially notable when utilizing the relatively fine gauge bristle wires.

The constricted neck 7 is immediately beyond the edge of the axial flange portion of disc 4 and the outwardly flared lip 8 is immediately beyond such neck. Lip 8 may be thus flared outwardly at an angle of about 35 to 45 to the brush axis. The bristle tufts 3, after being assembled as shown in FIG. 5, will ordinarily be trimmed prior to placement in cup 1 but may be trimmed thereafter. Lip 8 I is flared before such placement of the disc and tuft assembly in cup 1, and the cup then necked thereafter.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claimsor the equivalent of such be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. A power driven rotary end brush comprising a cup shaped holder, an axial stem extending therefrom for mounting in an appropriate chuck or the like, a sheet metal disc inserted in said cup against the bottom thereof having a generally axially extending peripheral flange portion, said flange portion having circularly arranged apertures therethrough, and twisted tufts of wire bristle material secured to said flange portion through such apertures and protruding from said cup shaped holder to provide a circular brush face having an open center, said cup having a constricted neck immediately beyond said flange portion to retain the disc and tuft assembly within said cup, and said cup having an outwardly flaring lip portion immediately beyond said neck.

2. The brush of claim 1, wherein the region internally of said peripheral flange portion of said disc is unobstructed to permit inward bulging of the basal portions of said tufts When the latter are flexed radially outwardly over said flared lip portion under the influence of centrifugal force.

3. The brush of claim 2, further characterized in that said wire bristle material has a diameter'on the order of .006 to .008 inch.

4. The brush of claim 2, further characterized in that said disc is centrally riveted to the bottom of said cup.

5. The brush of claim 2, further characterized in that said disc has a circle of small apertures therethrough inwardly of said circularly arranged apertures through which said tufts are secured to facilitate, deformation of said disc to provide said flange'portion without undue buckling and wrinkling thereof. I

6. The brush of claim 1, further characterized in that said disc is centrally secured to the bottom'of said cup.

7. .A power driven rotary end brush having a cup shaped holder adapted to be mounted for rotation about its axis, and an inner bristle retaining member Within said 7 cup having a single row of circularly arranged twisted tufts of brush bristles secured thereto and extending therefrom asubstantial distance beyond the lip of said cup, characterized in that said cup has a constricted neck closely beyond said member to secure said member and bristles within said cup, and an outwardly flaring lip portion immediately beyond said neck, the inner end portions of said bristles thus being unobstructed radially inwardly of said cup where secured to said retaining member to facilitate radially inward bulging thereof when the outer end portions of said bristles are flexed outwardly over said lip under the influence of centrifugal force in use.

8. The brush of claim 7, in which said bristles are of fine gauge wire.

9. The brush of claim 7, in which said outwardly flaring lip portion is disposed at an angle of about 35 to to the brush axis.

References Cited UNITED STATES PATENTS 2,449,158 9/1948 Benyak 15-198 2,480,877 9/1949 Peterson 15 2,755,496 7/1956 Benyak 15--198X 2,789,303 4/1957 Nelson 15--180 2,866,989 1/1959 Peterson et a1 l5198 2,989,767 6/1961 Charvat 15--180X 3,105,261 10/1963 Tilgner 15-180 CHARLES A. WILLMUTH, Primary Examiner.

P. FELDMAN, Assistant Examiner. 

